Shockproof safety screwdriver

ABSTRACT

The metallic tool to be protected against electrical shock in its use has a square inner end having a loose working fit in a square bore in the inner end of the plastic protective tubular body, and a coiled compression spring is caged between the inner end of the bore and the head on the blade. The spring is given a preload compression and subjected to further compression by a square drive shank of plastic material assembled behind the square head in the bore and retained by a crosspin extending transversely through a slot in the shank and mounted in the body. The blade is normally in retracted position in the body and arranged to be centered with respect to the work by entering it in the forward end of the bore, the blade being then pressed forward for connection with the work.

United States Patent [72] Inventor Theodore R. Wagner 257 Lansing St., Aurora, Colo. 80010 211 AppLNo. 774,322

[22] Filed Nov. 8, 1968 [45] Patented Jan. 19, 1971 {54] SHOCKPROOF SAFETY SCREWDRIVER 608,095 11/1960 Canada.

Primary Examiner-TherdhE. Condon Assistant Examiner-Roscoe V. Parker, .Ir. Attorney-Andrew F. Wintercorn ABSTRACT: The metallic tool to be protected against electrical shock in its use has a square inner end having a loose working fit in a square bore in the inner end of the plastic protective tubular body, and a coiled compression spring is caged between the inner end of the bore and the head on the blade. The spring is given a preload compression and subjected to further compression by a square drive shank of plastic material assembled behind the square head in the bore and retained by a crosspin extending transversely through a slot in the shank and mounted in the body. The blade is normally in retracted position in the body and arranged to be centered with respect to the work by entering it in the forward end of the bore, the blade being then pressed forward for connection with the work.

' PATENTEUIYJAAN 1" 9 Ian 7 INVENTORI THEODORE R. WAGNER Any.

Y Thesarne reference parts throughout the views.

This invention relatestoa new andimprovedshock-proof,

3 FIGS is a similar section showing the tool in use, and

FIG. '4 is across section on line4-f4 of FIG. 3 one larger The'only metal parts (and, therefore, electrical conductors) are the screwdriverblade 5, coiled compressionspring 6, and hollow rivet or crosspin with its fastening screw 8. The blade 5 has a square head 9 on its inner end slidable freely in a square bore 10 in the enl argedfinner end portion 11 of the molded cylindrical plastictubular body 12. The spring 6 mentioned before is compressed to a certain preload and caged in the bore l0 betwee'nthe head 9 onthe screwdriver blade and an annular shoulder '13 provided at the inner end of the'bore l0 7 where the blades extends forwardly .throu ghcthe reduced bore 14 to the forward end of, the bodyIZ to the usual bit end 15 7 adapted for entry in the'slot 16 of a screw 17L The forward end of the body 12 is preferably beveled as shown at 18, to' afford a better view of the screw headin using the tool, when the head numerals areapplied to corresponding 21, and, assuming it is the intention to unscrew the screw 17, the brace 21' will be turned accordingly in a counterclockwise direction to unscrew it.-There is no need for concern regarding electric shock because,even though the metallic blade 5 is in contact with'the metallic-screw 17, there can be no electri calcurrent flow beyond the blade 5, because all of the rest of the screwdriver therebeyond is in insulated relationship to the blade 5, and, of course, it makes no difference if thevbrace 21 is of conductive material, inasmuch as the driving shank l9 thoroughly insulates the brace from the screwdriver assembly.

' Obviously, there is nothing to get out oforder or break with normal usage, and, if the screwdriver bit 15 gets worn and the blade 5 should be replaced, it is a simple matter to disassemble the tool at 7-8 in order to replace the blade. While a conventional type screwdriver blade is shown at 545 it will, of course, be understood that a Phillips type may be p ovided and, in fact, any other tool of acorresponding size.

It is believed the foregoingdescription conveys agood understanding of the objects and advantages of my invention. The appended claims have been drawn to cover all legitimate modifications and adaptations,

l.' A tool of the character jdBSCI'lb Bd comprising an elongated tubular body of electrically insulatingmaterial providing of the screw is engaged in the forward encl of 'the bore '14, as

seen in FIG. 3. The square plastic drive shank 19, which has a loose working fit in the square bore 10 behind the head end 9, of the screwdriver blade 5, has an elongated slot20 provided in its forward end in'which the hollow rivet or crosspin 7,

previously mentioned, has; a loose working fit, this rivet or pin sewing to retain the drive shank 19in assembled relationship to the rest of the tool while allowing the shank 19 to be moved forwardly relative to the plastic body 12, as seen in FIG. 3, compressing the spring 6 and holding the bit end 15 of the screwdriver blade in the slot 16 in the head of the screw 17 while the usualbrace 21 is being used to drive the screwdriver blade 5. While I have shown at 21 a brace, it should be clear that a handle maybe used, as on 'a conventional screwdriver,

or I may, drive the shank 19 by applying thereto the torque apa full length longitudinal bore havingan enlarged elongated rear end portion of polygonal cross section, a metallicblade having a reduced longitudinal shank portion received in said bore with an enlarged polygonal rear head end nonrotatable in the enlarged inner end portion of the bore, spring means compressed between one end of said enlarged bore portion and said head, and an elongated drive shankfof electrically insulating material of polygonal form movable endwise but nonrotatably in the enlarged portion of said bore in said body to transmit endwise movement to said blade forwardly relative to said body and also transmit drive thereto in either direction.

2. A tool as set forth in claim 1 wherein the spring meansis under a preload compression, said bladebeing limited in its rearward movement with respect to said body to maintain said preload,

3. Atool as set forth in claim 1 wherein the spring means is undera preload compression, said blade being limited in its rearward movement with respect to said'body to maintain said preload, the last mentioned means comprising a crosspin in the rear end portion of the body extending through a longitudinal slot provided in the driving shank.

4. A tool as set forth in claim 1 wherein the spring means is under a preloadcompression, said blad'e'being limited in its rearward movement with respect to said body to. maintain said preload, the last mentioned means comprising a crosspin in the rear end portion of the body extending through a longitudinal slot provided in the driving shank and means for 

1. A tool of the character described comprising an elongated tubular body of electrically insulating material providing a full length longitudinal bore having an enlarged elongated rear end portion of polygonal cross section, a metallic blade having a reduced longitudinal shank portion received in said bore with an enlarged polygonal rear head end nonrotatable in the enlarged inner end portion of the bore, spring means compressed between one end of said enlarged bore portion and said head, and an elongated drive shank of electrically insulating material of polygonal form movable endwise but nonrotatably in the enlarged portion of said bore in said body to transmit endwise movement to said blade forwardly relative to said body and also transmit drive thereto in either direction.
 2. A tool as set forth in claim 1 wherein the spring means is under a preload compression, said blade being limited in its rearward movement with respect to said body to maintain said preload.
 3. A tool as set forth in claim 1 wherein the spring means is under a preload compression, said blade being limited in its rearward movement with respect to said body to maintain said preload, the last mentioned means comprising a crosspin in the rear end portion of the body extending through a longitudinal slot provided in the driving shank.
 4. A tool as set forth in claim 1 wherein the spring means is under a preload compression, said blade being limited in its rearward movement with respect to said body to maintain said preload, the last mentioned means comprising a crosspin in the rear end portion of the body extending through a longitudinal slot provided in the driving shank and means for releasably securing said crosspin in assembled relation to the rear end portion of said body. 